Predictive effects of pre-stimulus energy and phase in alpha and beta bands on discrimination accuracy and visual awareness

Abstract

People are often unaware of objects that are easily aware of at other times. Because the visual stimulus itself is constant, this change in conscious experience may be related to changes in the state of the brain. It is mainly measured by the power and phase of the oscillation in the α band before the stimulus. At present, the effects of prestimulus α band activities on visual awareness in discrimination tasks were not consistent, and there were few studies on prestimulus β band. In this study, the low-contrast stimulus paradigm combined with EEG time-frequency and different awareness perception levels were added to explore the predictive effects of prestimulus α and β on visual awareness in discrimination task. It was found that the main effect of accuracy of α and β was significant, with correct was significantly lower than false. The main effect of awareness level of α was significant. The main effect of phase of accuracy of α was insignificant, but was  significant on β. The main effect of phase of awareness level of α was insignificant, but was significant on β. The result showed that the power in the prestimulus α band was significantly lower under correct than false condition.The results showed that the power in the prestimulus α (but not the phase) predicted the accuracy and visual awareness, and the power in the prestimulus β predicted the accuracy, but not the visual awareness. The phase of prestimulus β predicted the accuracy and visual awareness.